November Log (Arnøya / Kågen / Laukøya and Tromsø)
Notes
- air temperatures below are measured on sea level
- if clear sky, assume inversion
2025-11-01—2025-11-05 (A)
- Air: a bit above zero to up to +5 degrees with overnight refreeze down to the sea level
- Wind: periods with SW-S-SØ moderate and strong breeze
- Precipitation: mostly overcast with some rain showers
- Observations: some remaining, most likely isothermal MF slabs, mostly on E slopes where there was no direct sun affecting the slopes
2025-11-06—2025-11-07 (A)
- Air: temperatures 3-7 degrees
- Wind: SW-N-NW fresh to strong breeze
- Precipitation: mostly overcast with some occasional rain showers
- Observations: a grand reset where at least Arnøya mountains have mostly re-frosen clustered wet snow on eastern slopes which is hopefully wet so new load of snow will bind well
Wind-, precipitation- and sunward oriented southern and western slopes are more or less without snow so we are starting from scratch here
2025-11-08—2025-11-10 (A)
- Air: dropping temps towards and slightly above 0
- Wind: N-NW up to strong breeze and long periods with near gale and gale
- Precipitation: heavy rain-, hail- and snow showers
- Observations: development of a wet layer close to the ground, covered by right side up snow as the tail of the frontal system is cold
2025-11-11 (A)
- Air: temp slightly below 0
- Wind:SW up fresh breeze
- Precipitation: periods with sun and overcast
- Observations: could mean some cross loading snow traveling "back" where it came from but there is not that much snow available for transport
2025-11-12—2025-11-14 (A)
- Air: temps around 0
- Wind: E-NE-N up to strong breeze and long periods with near gale winds
- Precipitation: heavy snow showers
- Observations: most of the snow is being blown away or evaporating so there is really huge differences between the areas (pockets) of deposit snow and blown ones (most of the places based on observations). As the wind calms down last day, the deposit areas start to fill with snow
2025-11-15—2025-11-16 (A) (T)
- Air: couple of minus degrees
- Wind: S-SW light breeze
- Precipitation: overcast and snow showers
- Observations: Past: Huge difference in amount of snow - comparing Arnøya and Tromsø. This due to the winds vs low winds in Tromsø. About 60cm of new snow in total in Tromsø. Dry snow with some wet layer lower / all the way down, this will surely cause a trouble in the future. Slabs on "southern" slopes assuming it was blowing from "north".
Now: fresh wind slabs on NE-N slopes where enough snow available for transport
2025-11-17—2025-11-23 (T)
- Air: stable temperature couple of degrees minus zero (down to minus 10 degrees 22-23.11.)
- Wind: SW-S strong breeze in the beginning of the period, then breeze and light breeze
- Precipitation: overcast and constant snow showers
- Observations: loading of the northern slopes with some more even distribution in the second half of the period
2025-11-24—2025-11-26 (T)
- Air: temps around zero with coming thaw last day
- Wind: periods with light- to moderate S breeze and increasing to S strong breeze
- Precipitation: snow showers and wetter snow showers last day
- Observations: about 30 cm of partially settled snow last 10 days, mostly S-SW winds mean overloading of N-E slopes.
Being out of touch with snowpack due to the travel but I would expect some dry- or wet slab slides
2025-11-27—2025-11-28 (T)
- Air: temps up to +6 degrees with no overnight refreeze
- Wind: first day southern up to near gale - progressively dying the second day
- Precipitation: hail / graupel / rain / snow showers
- Observations: saturation of new snow even higher up in the mountains. Plus load of new and wet snow in leeward pockets / aspects. Could mean combination of dry and wet slides on northern->eastern slopes where applicable.
Being out of sync after the travel so not sure about the snow / layers in the snowpack.
2025-11-29—2025-11-30 (T)
- Air: dropping temps towards zero
- Wind: SW->W increasing breeze to gale winds
- Precipitation: wintry mix and snow showers
- Observations: fresh wind slabs on eastern aspects and growing of a rain/MF crust closer to the sea level
Summary
Overall pattern:
November marked the transition into a true winter snowpack, with alternating warm/wet cycles, cold spells, strong wind events, and repeated snowfalls. The snowpack varied greatly between Arnøya and Tromsø, with Arnøya remaining more wind-affected and Tromsø receiving deeper accumulations.
Temperatures:
Ranged from mild (+6 °C) to cold (–10 °C). Several warm pulses caused wet‑snow problems and MF crust formation, while colder intervals promoted bonding or TG‑driven weakening depending on snow depth.
Wind:
Highly variable, frequently strong, and often shifting quickly (SW, S, SE, N, NE). Results included:
- Widespread scouring, especially high up
- Frequent slab formation on E, NE, and N slopes
- Large spatial differences in snow depth between windward and leeward faces
- Arnøya: more scouring and transport
- Tromsø: calmer periods allowing deeper accumulation (~60 cm at one point)
Precipitation:
Included heavy snow, snow showers, hail, graupel, mixed precipitation, and multiple
rain-on-snow events. The rain cycles created MF crusts and slippery layers, especially below 400–700 masl.
Snowpack evolution:
- Early Nov: isothermal MF remnants; unstable wet layers; limited bonding.
- 6–7 Nov: first “reset” — refrozen clustered wet snow on E slopes; S/W slopes nearly bare.
- 8–10 Nov: heavy showers + gale → wet basal layer + right‑side‑up structure above.
- 11 Nov: new cross-loading but little snow to transport.
- 12–14 Nov: strong winds → dramatic spatial variability; deposits forming as wind calmed.
- 15–16 Nov: huge contrast Arnøya vs Tromsø (Tromsø ~60 cm new) → new slabs + wet layers.
- 17–23 Nov: continuous loading of N slopes (T).
- 24–26 Nov: ongoing loading (T); expected dry/wet slab issues.
- 27–28 Nov: major warm event (+6 °C) → saturation of snowpack, poor bonding.
- 29–30 Nov: colder + new wind slabs; MF crust forming near sea level.
Key layers entering December:
- Multiple MF crusts at various elevations.
- A wet basal layer from repeated warm rain events.
- Stiff and soft slabs distributed unevenly depending on wind exposure.
- Poorly bonded new layers over old rain crusts.
- Great spatial variability (thin/scoured vs deep deposition).
- A mix of graupel, wet snow, slabs, and wind eroded surfaces across both regions.
Overall:
November ended with a snowpack that was deeper and more structured than October, but still highly variable and heavily influenced by wind and temperature swings. December would bring the first prolonged cold periods that begin defining deeper-season persistent weak layers.
